Illumination device and electronic apparatus including the same

ABSTRACT

Provided in an illumination device including a display panel including a first surface configured to display an image, a second surface opposite to the first surface, a plurality of display pixels disposed between the first surface and the second surface, and a transmission window configured to transmit light incident on the second surface through the first surface, a light source disposed at the second surface of the display panel and configured to emit light to an object toward the display panel, and a light deliverer disposed between the light source and the display panel, the light deliverer configured to deliver the light emitted from the light source to the object as flood illumination through the transmission window.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of U.S. ProvisionalPatent Application No. 62/729,696, filed on Sep. 11, 2018 in the UnitedStates Patent and Trademark Office, and claims priority from KoreanPatent Application No. 10-2019-0008607, filed on Jan. 23, 2019 in theKorean Intellectual Property Office, the disclosures of which areincorporated herein by reference in their entireties.

BACKGROUND 1. Field

Example embodiments of the present disclosure relate to illuminationdevices and electronic apparatuses including the same.

2. Description of the Related Art

In mobile and wearable devices, there is a demand for various sensorssuch as an iris recognition sensor, a facial sensor, a depth sensor,etc., and various light sources and optical parts for this purpose areprovided together with the mobile and wearable devices.

In recent years, a display of a smart phone has been developed with afull screen display, and since a display surface covers almost all ofthe area of a front surface of the device, it is not easy to arrange alight source for such a sensor appropriately.

SUMMARY

One or more example embodiments provide illumination devices that emitlight to a front side of a display panel.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of example embodiments.

According to an aspect of an example embodiment, there is provided anillumination device including a display panel including a first surfaceconfigured to display an image, a second surface opposite to the firstsurface, a plurality of display pixels disposed between the firstsurface and the second surface, and a transmission window configured totransmit light incident on the second surface through the first surface,a light source disposed at the second surface of the display panel andconfigured to emit light to an object toward the display panel, and alight deliverer disposed between the light source and the display panel,the light deliverer configured to deliver the light emitted from thelight source to the object as flood illumination through thetransmission window.

The light deliverer may include a plurality of nanostructures having ashape dimension smaller than that of a wavelength of the light emittedfrom the light source.

The transmission window may include a plurality of non-pixel regions,the plurality of display pixels may be configured to reflect the lightemitted from the light source, and the plurality of display pixels andthe plurality of non-pixel regions may be alternately provided.

A fill factor of a cross-sectional area occupied by the plurality ofdisplay pixels on the first surface may be 50% to 60%.

The light deliverer may include a substrate including a third surfacefacing the display panel and a fourth surface facing the light source, ameta-mirror disposed on the third surface and including a plurality offirst nanostructures having a shape dimension smaller than that of awavelength of the light emitted from the light source, wherein theplurality of first nanostructures have a shape distribution such thatthe plurality of first nanostructures is configured to operate as amirror in which an aperture is formed in a center portion, and ameta-lens disposed on the fourth surface and including a plurality ofsecond nanostructures having a shape dimension smaller than that of thewavelength of the light emitted from the light source, wherein theplurality of second nanostructures have a shape distribution such thatthe light emitted from the light source is directed toward the aperture.

The shape distribution of the plurality of first nanostructures may bedetermined such that the meta-mirror is configured to operate as aconcave mirror with respect to the display panel.

The light source may be provided asymmetrically with respect to theaperture.

The light deliverer may include a substrate including a third surfacefacing the display panel and a fourth surface facing the light source, afirst meta-lens disposed on the third surface and including a pluralityof first nanostructures having a shape dimension smaller than that ofthe wavelength of the light emitted from the light source, wherein theplurality of first nanostructures have a shape distribution such thatthe plurality of first nanostructures are configured to converge thelight to a plurality of non-pixel regions, and a second meta-lensdisposed on the fourth surface and including a plurality of secondnanostructures having a shape dimension smaller than that of thewavelength of the light emitted from the light source, wherein theplurality of second nanostructures have a shape distribution such thatthe plurality of second nanostructures collimate the light emitted fromthe light source to correspond to the first meta-lens.

The shape distribution of the plurality of first nanostructures may bedetermined such that the first meta-lens is configured to operate as aplurality of first convex lenses provided to face the plurality ofnon-pixel regions, and the shape distribution of the plurality of secondnanostructures may be determined such that the second meta-lens isconfigured to operate as a plurality of second convex lenses provided toface the plurality of first convex lenses, respectively.

The shape distribution of the plurality of first nanostructures may bedetermined such that the first meta-lens is configured to operate as aplurality of first convex lenses provided to face the plurality ofdisplay pixels and the plurality of non-pixel regions, and the shapedistribution of the plurality of second nanostructures may be determinedsuch that the second meta-lens is configured to operate as a pluralityof second convex lenses provided to face the plurality of first convexlenses, respectively.

The light source may include a plurality of light emitting elementsarranged to correspond to the plurality of display pixels and theplurality of non-pixel regions, respectively.

The illumination device may further include a photodetector configuredto sense an amount of the light emitted from the light source reflectedfrom the plurality of display pixels, and a light source controllerconfigured to select and drive a number of the plurality of lightemitting elements based on the amount of light detected by thephotodetector.

The shape distribution of the plurality of first nanostructures and theshape distribution of the plurality of second nanostructures may bedetermined such that the first meta-lens and the second meta-lens eachis configured to operate as a convex lens, respectively.

The illumination device may further include a microlens array disposedbetween the first meta-lens and the display panel, the microlens arrayincluding a plurality of microlenses facing the plurality of non-pixelregions, respectively.

The shape distribution of the plurality of first nanostructures and theshape distribution of the plurality of second nanostructures may bedetermined such that a focal length of the first meta-lens is shorterthan a focal length of the second meta-lens.

The illumination device may further include a reflective structureprovided between the light deliverer and the display panel, thereflective structure configured to reflect the light emitted from thelight source and directed toward regions of the plurality of displaypixels to be directed toward the non-pixel region.

The light deliverer may include a substrate including a third surfacefacing the display panel and a fourth surface facing the light source,and a plurality of nanostructures disposed on the fourth surface andhaving a shape dimension smaller than that of a wavelength of light ofthe light source, the plurality of nanostructures having a shapedistribution shaping the light emitted from the light source such thatan amount of light directed toward the reflective structure from thelight source is similar to an amount of light directed directly towardthe transmission window from the light source.

The transmission window may include one region in which the plurality ofdisplay pixels are not provided.

A diameter of the transmission window may be 5 mm to 10 mm.

The light deliverer may include a plurality of nanostructures of a shapedimension smaller than that of a wavelength of light emitted from thelight source, and the plurality of nanostructures may have a shapedistribution such that the light emitted from the light source isfocused on the first surface to a beam cross-sectional sizecorresponding to the transmission window, and then diffused and emittedto a front side of the display panel.

According to another aspect of an example embodiment, there is providedan electronic apparatus including an illumination device including adisplay panel including a first surface configured to display an image,a second surface opposite to the first surface, a plurality of displaypixels disposed between the first surface and the second surface, and atransmission window configured to transmit light incident on the secondsurface through the first surface, a light source disposed at the secondsurface of the display panel and configured to emit light to an objecttoward the display panel, and a light deliverer disposed between thelight source and the display panel, the light deliverer configured todeliver the light emitted from the light source to the object as floodillumination through the transmission window, a sensor configured toreceive light reflected from the object, and a processor configured toobtain information about the object based on the light received by thesensor.

According to another aspect of an example embodiment, there is providedan illumination device including a display panel including a firstsurface configured to display an image, a second surface opposite to thefirst surface, a plurality of display pixels disposed between the firstsurface and the second surface and configured to reflect light incidentfrom the second surface, and a transmission window configured totransmit the light incident on the second surface through the firstsurface, a light source disposed at the second surface of the displaypanel and configured to emit light to an object toward the displaypanel, a light deliverer disposed between the light source and thedisplay panel and including a third surface and a fourth surfaceopposite to the third surface, the light deliverer configured to deliverthe light emitted from the light source to the object as floodillumination through the transmission window, a meta-mirror disposed onthe third surface of the light deliverer and including a plurality offirst nanostructures having a sub-wavelength dimension smaller, and ameta-lens disposed on a fourth surface of the light deliverer andincluding a plurality of second nanostructures having a sub-wavelengthdimension.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or other aspects will become apparent and more readilyappreciated from the following description of example embodiments, takenin conjunction with the accompanying drawings in which:

FIG. 1 is a cross-sectional view showing a schematic configuration of anillumination device according to an example embodiment;

FIG. 2A is a plan view showing an exemplary pixel arrangement of adisplay panel employed in the illumination device of FIG. 1;

FIG. 2B is a plan view showing a pixel arrangement of a display panelaccording to a comparative example;

FIG. 3A is a detailed enlarged view showing a part of an upper region ofa light deliverer employed in the illumination device of FIG. 1;

FIG. 3B is a detailed enlarged view showing a part of a lower region ofthe light deliverer employed in the illumination device of FIG. 1;

FIG. 4 is a cross-sectional view showing a schematic configuration of anillumination device according to another example embodiment;

FIG. 5 is a cross-sectional view showing a schematic configuration of anillumination device according to another example embodiment;

FIG. 6 is a cross-sectional view showing a schematic configuration of anillumination device according to another example embodiment;

FIG. 7 is a cross-sectional view showing a schematic configuration of anillumination device according to another example embodiment;

FIG. 8 is a cross-sectional view showing a schematic configuration of anillumination device according to another example embodiment;

FIG. 9 is a cross-sectional view showing a schematic configuration of anillumination device according to another example embodiment;

FIG. 10 is a cross-sectional view showing a schematic configuration ofan illumination device according to another example embodiment;

FIG. 11 is a cross-sectional view showing a schematic configuration ofan illumination device according to another example embodiment;

FIG. 12 is a cross-sectional view showing a modified example of areflective structure that may be employed in the illumination device ofFIG. 11.

FIG. 13 is a cross-sectional view showing a schematic configuration ofan illumination device according to another example embodiment;

FIG. 14 is a block diagram showing a schematic configuration of anelectronic apparatus according to an example embodiment; and

FIG. 15 is a perspective view showing an example of an externalappearance of the electronic apparatus of FIG. 14.

DETAILED DESCRIPTION

Reference will now be made in detail to example embodiments of which areillustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the exampleembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theexample embodiments are merely described below, by referring to thefigures, to explain aspects. Sizes of components in the drawings may beexaggerated for convenience and clarity of description. On the otherhand, the example embodiments described below are merely exemplary, andvarious modifications may be made from these example embodiments. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items. Expressions such as “at leastone of,” when preceding a list of elements, modify the entire list ofelements and do not modify the individual elements of the list. Forexample, the expression, “at least one of a, b, and c,” should beunderstood as including only a, only b, only c, both a and b, both a andc, both b and c, or all of a, b, and c.

It will be understood that, when a component is referred to as being“on” another component, it may be directly or indirectly on the othercomponent.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that, when a portion “includes”an element, another element may be further included, rather thanexcluding the existence of the other element, unless otherwisedescribed.

Also, the terms, such as “ . . . unit” or “module”, used herein refer toa unit that processes at least one function or operation, and the unitmay be implemented by hardware or software, or by a combination ofhardware and software.

FIG. 1 is a cross-sectional view showing a schematic configuration of anillumination device 1001 according to an example embodiment. FIG. 2A isa plan view showing an example pixel arrangement of a display panel 300employed in the illumination device 1001 of FIG. 1. FIG. 2B is a planview showing a pixel arrangement of a typical display panel 30 accordingto a comparative example. FIG. 3A is a detailed enlarged view showing apart of an upper region of a light deliverer 201 employed in theillumination device 1001 of FIG. 1. FIG. 3B is a detailed enlarged viewshowing a part of a lower region of the light deliverer 201 employed inthe illumination device 1001 of FIG. 1.

The illumination device 1001 includes the display panel 300 providedwith a transmission window for transmitting light, a light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and the light deliverer 201 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 such that the light is emitted to the transmissionwindow of the display panel 300.

The light source 110 may include an array of a plurality of lightemitting elements 112. The light emitting element 112 may include anlight emitting diode (LED) or a laser diode emitting laser light. Thelight emitting element 112 may include a vertical cavity surfaceemitting laser (VCSEL). The light emitting element 112 may include, forexample, an active layer formed of an III-V semiconductor material or aII-VI semiconductor material and having a multi-quantum well structure,but is not limited thereto. The light emitting element 112 may emitlaser light of wavelength of approximately 850 nm or 940 nm, or may emitnear-infrared rays or light of a visible light wavelength band. Thewavelength of the light emitted from the light emitting element 112 isnot particularly limited, and the light emitting element 112 that emitslight in a desired wavelength band may be used.

The display panel 300 includes a first surface 300 a on which an imageis displayed and a second surface 300 b opposite to the first surface300 a. A plurality of display pixels 310 are disposed between the firstsurface 300 a and the second surface 300 b. Hereinafter, a surface onwhich an image is displayed on the display panel 300 may be a displaysurface. A non-pixel region 320 is disposed between the display pixels310 and is a transparent window through which light is transmitted.Hereinafter, the non-pixel region 320 may be a transmission window.

The display panel 300 includes a display element, for example, a liquidcrystal display (LCD), an organic light emitting diode (OLED). When thedisplay element is the LCD, a light source for the display panel 300 isseparately provided. The display element is divided into a plurality ofregions that are controlled to be on/off in accordance with imageinformation, and each region may be a display pixel 310. The displaypixel 310 includes the display element and circuit elements forcontrolling the display element, and is an opaque region due to a metalmaterial included therein. That is, light incident on the display pixel310 from below the display panel 300 is reflected and is not emitted tothe front side of the display panel 300. The non-pixel region 320 is apixel-free region. The non-pixel region 320 is a region in which atleast a part of the circuit elements for controlling the displayelement, for example, a metal pixel electrode, is not provided and maytransmit light. Accordingly, the light incident on the non-pixel region320 may be emitted to the front side of the display panel 300.

As shown in FIG. 2A, the plurality of display pixels 310 and theplurality of non-pixel regions 320 may be alternately arranged. Althoughthe display pixel 310 and the non-pixel region 320 have the same size inFIG. 2A, embodiments are not limited thereto. The size of the non-pixelregion 320 may be equal to or less than that of the display pixel 310.For example, a fill factor of a cross-sectional area occupied by theplurality of display pixels 310 on the display surface may be about 50%to about 60%.

Referring to FIG. 2B of the comparative example, in a display panel 30,the display pixels PX are distributed over an entire display surface.Because the display pixel PX includes a metal material that may nottransmit light, such as a pixel electrode, etc., the display pixel PXdoes not transmit light incident from a rear side of the display panel30.

The illumination device 1001 of an example embodiment uses the displaypanel 300 in which half of display pixels of a related display panel arereplaced with a non-pixel region to illuminate the front side of thedisplay panel 300 with the light of the light source 110 disposed on therear side of the display panel 300.

The light deliverer 201 is disposed between the light source 110 and thedisplay panel 300 such that the light emitted from the light source 110passes through the transmission window of the display panel 300 and isdelivered to an object as flood illumination. The light deliverer 201includes a plurality of nanostructures having a shape dimension smallerthan the wavelength of the light of the light source 110 and shapes ofthe plurality of nanostructures or distribution rules of thenanostructures are set such that the operations described above areimplemented.

The light deliverer 201 may include a meta-mirror 220 having an apertureAP formed in one side and a meta-lens 230 on the other side. Forexample, the light deliverer 201 includes a substrate SU provided with athird surface SUa facing the display panel 300, a fourth surface SUbfacing the light source 110, the meta-mirror 220 disposed on the thirdsurface SUa and having the aperture AP in the center thereof and themeta-lens 230 disposed on the fourth surface SUb.

Referring to FIG. 3A, the meta-mirror 220 disposed on the third surfaceSUa includes a plurality of first nanostructures NS1. The plurality offirst nanostructures NS1 are distributed on the third surface SUa excepton the aperture AP. That is, the aperture AP is a region through whichthe light of the light source 110 is transmitted because the firstnanostructure NS1 is not formed on the third surface SUa. A thickness tor a width D, which is a dimension defining a shape of the firstnanostructure NS1, may be less than the wavelength of the light emittedfrom the light source 110. The first nanostructure NS1 may have acylindrical shape, an elliptical column, a polygonal column, and variousother shapes. The first nanostructure NS1 includes a material having arefractive index higher than that of the substrate SU, and may include amaterial including any one of, for example, monocrystalline silicon,polycrystalline silicon, amorphous silicon, silicon nitride (Si₃N₄),gallium phosphide (GaP), titanium oxide (TiO₂), aluminum antimonide(AlSb), aluminum arsenide (AlAs), aluminum gallium arsenide (AlGaAs),aluminum gallium indium phosphide (AlGaInP), boron phosphide (BP), andzinc germanium phosphide (ZnGeP₂). The substrate SU supports theplurality of first nanostructures NS1 and may include a material havinga refractive index lower than that of the first nanostructure NS1. Arefractive index difference between the substrate SU and the firstnanostructure NS1 may be about 0.5 or more. The substrate SU may includea polymer, for example, silicon oxide (SiO₂), transparent conductiveoxide (TCO), polycarbonate (PC), polystyrene (PS), or poly(methylmethacrylate) (PMMA), but is not limited thereto.

The first nanostructure NS1 may have a shape dimension of asub-wavelength smaller than the wavelength of the light emitted from thelight source 110. The first nanostructure NS1 may reflect light of apredetermined wavelength band by a specific shape of the firstnanostructure NS1, an arrangement form, and the like. The shapedistribution of the plurality of first nanostructures NS1 may bedetermined such that the meta-mirror 220 operates as a concave mirrorwith respect to the display panel 300. Here, the shape distribution maybe at least one of a shape, size of the first nanostructure NS1, thesize, shape distribution of the plurality of first nanostructures NS1,an arrangement pitch of the plurality of first nanostructures NS1, and adistribution of the arrangement pitch of the first nanostructure NS1. Atleast one of the thickness, the width, and the arrangement pitch of thefirst nanostructure NS1 may be half or less of the wavelength of thelight emitted from the light source 110. In FIG. 3A, the firstnanostructure NS1 has a certain size and has a certain interval, butthis is an example, and embodiments are not limited thereto.

Referring to FIG. 3B, the meta-lens 230 disposed on the fourth surfaceSUb includes a plurality of second nanostructures NS2. The plurality ofsecond nanostructures NS2 may include a material having a refractiveindex higher than that of the substrate SU, have the shape dimension ofthe sub wavelength and have a shape distribution to operate as a convexlens for collecting the light emitted from the light source 110 towardthe aperture AP. The second nanostructure NS2 may have the shapedistribution in which the width D decreases from the center to theperiphery. These rules may be repeated in a direction from the center tothe periphery. A repetition period may not be constant. The shapedistribution of the second nanostructure NS2 may be set such that a beamcross-sectional size on the third surface SUa is similar to that of theaperture AP considering a size of the aperture AP, a distance to theaperture AP, etc.

Referring to FIG. 1, a path of the light emitted from the light source110 will be described.

The light emitted from the light source 110 is directed toward theaperture AP on the upper side of the light deliverer 201 by themeta-lens 230 below the light deliverer 201. The light is directedtoward the display panel 300 through the aperture AP and passes throughthe transmission window of the display panel 300, that is, the pluralityof non-pixel regions 320, to illuminate the front side of the displaypanel 300. The non-pixel region 320 is uniformly distributed on thefirst surface 300 a, which is the display surface of the display panel300. Therefore, illumination light may be flood illumination light thatsubstantially uniformly illuminates an object in front of the displaypanel 300.

The light emitted toward the display pixel 310 of the display panel 300is reflected without passing through the display pixel 310. Thereflected light may be reflected by the meta-mirror 220 and directedtoward the display panel 300 again. The light that is changed in thepath toward the non-pixel region 320 of the display panel 300 mayilluminate the front side of the display panel 300. As described above,the light that is reflected without passing through the display pixel310 is recycled by the meta-mirror 220, and thus, light efficiency maybe increased. Also, because the first nanostructures NS1 are arrangedsuch that the meta-mirror 220 serves as a concave mirror, the efficiencyof the recycled light contributing to the illumination light may beincreased.

FIG. 4 is a cross-sectional view showing a schematic configuration of anillumination device 1002 according to another example embodiment.

The illumination device 1002 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and a light deliverer 202 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 300.

The illumination device 1002 of an example embodiment differs from theillumination device 1001 of FIG. 1 in that the light source 110 isarranged asymmetrically with respect to the aperture AP of the lightdeliverer 202, in order to increase the efficiency of the recycledlight, and the remaining configuration thereof is substantially thesame.

The light reflected from the display pixel 310 of the display panel 300may be recycled in case that the light reaches the meta-mirror 220, andthe light traveling toward the aperture AP again is not recycled. Byarranging the aperture AP and the light source 110 asymmetrically, theamount of light reflected by the display pixel 310 toward the apertureAP is reduced and the efficiency with which the light reflected from thedisplay pixel 310 is recycled may be increased.

FIG. 5 is a cross-sectional view showing a schematic configuration of anillumination device 1003 according to another example embodiment.

The illumination device 1003 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and a light deliverer 203 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 300.

In the illumination device 1003 of the example embodiment, the lightdeliverer 203 includes a first meta-lens 232 on an upper side thereofand a second meta-lens 233 on a lower side thereof so as to collect thelight emitted the light source 110 to each of the plurality of non-pixelregions 320.

The first meta-lens 232 disposed on the third surface SUa of thesubstrate SU includes a plurality of first nanostructures NS3. A shapedistribution of the plurality of first nanostructures NS3 is set suchthat the first nanostructures NS3 operates as a plurality of convexlenses converging light to the plurality of non-pixel regions 320,respectively.

The second meta-lens 233 disposed on the fourth surface SUb of thesubstrate SU includes a plurality of second nanostructures NS4. Theplurality of second nanostructures NS4 may have a shape distribution tocollimate the light of the light source 110 to correspond to the firstmeta-lens 232. A shape distribution of the plurality of secondnanostructures NS4 is set such that the second nanostructures NS4 mayoperate as a plurality of convex lenses. As shown in FIG. 5, the shapedistribution of the plurality of second nanostructures NS4 may be setsuch that the second nanostructures NS4 operate as a plurality of convexlenses respectively corresponding to the plurality of convex lenses ofthe first meta-lens 232.

The plurality of light emitting elements 112 included in the lightsource 110 may be arranged at locations corresponding to the pluralityof non-pixel regions 320. The light emitted from the light source 110may be collimated as parallel light in the second meta-lens 233 anddirected toward the first meta-lens 232. The light of the firstmeta-lens 232 may be converged to each of the plurality of non-pixelregions 320 and spread out toward a front side of the display panel 300.

FIG. 6 is a cross-sectional view showing a schematic configuration of anillumination device 1004 according to another example embodiment.

The illumination device 1004 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and a light deliverer 204 disposed between the light source110 and the display panel 300 to transmit the light of the light source110 to the transmission window of the display panel 300.

The illumination device 1004 of the example embodiment differs from theillumination device 1003 of FIG. 5 in a detailed shape distribution ofthe first nanostructures NS3 and second nanostructures NS4 respectivelyprovided in a first meta-lens 234 and a second meta-lens 235constituting the light deliverer 204.

A shape distribution of the first nanostructure NS3 of the firstmeta-lens 234 is set such that the first nanostructure NS3 operates as aconvex lens facing the plurality of display pixels 310 and the pluralityof non-pixel regions 320, respectively. Accordingly, the plurality offirst nanostructures NS3 are formed not only at locations correspondingto the display pixels 310 but also at locations corresponding to thenon-pixel regions 320.

A shape distribution of the second nanostructure NS4 of the secondmeta-lens 235 is also set such that the second nanostructure NS4operates as a convex lens facing the plurality of display pixels 310 andthe plurality of non-pixel regions 320, respectively. The plurality ofsecond nanostructures NS3 are formed not only at locations correspondingto the display pixels 310 but also at locations corresponding to thenon-pixel regions 320.

The above-described configuration of the light deliverer 204 mayfacilitate the alignment of the light deliverer 204 and the displaypanel 300 in a manufacturing process. The plurality of firstnanostructures NS3 and the second nanostructure NS4 disposed to face thedisplay pixel 310 do not contribute to an optical path for illuminatinga front side of the display panel 300 but may reduce alignment errorsduring manufacture when compared with the structure of the lightdeliverer 203 of the illumination device 1003 of FIG. 5, by disposingthe plurality of first nanostructures NS3 and the second nanostructuresNS4 at locations corresponding to both of the display pixel 310 and thenon-pixel region 320.

FIG. 7 is a cross-sectional view showing a schematic configuration of anillumination device 1005 according to another example embodiment.

The illumination device 1005 of the example embodiment is different fromthe illumination device 1004 of FIG. 6 in that the plurality of lightemitting elements 112 provided in the light source 111 are arranged tocorrespond to the plurality of display pixels 310 and the plurality ofnon-pixel regions 320, respectively, and the illumination device 1005further includes a photodetector 400 and a light source controller 500.

The plurality of light emitting elements 112 provided in the lightsource 111 may be individually controlled by the light source controller500 to be on/off. The light emitting elements 112 may be connected inunits of columns such that the light emitting elements 112 ofeven-numbered columns and the light emitting elements 112 ofodd-numbered columns may be controlled together to be on/off.

By the above configuration, the light source 111, the light deliverer204, and the display panel 300 may be more easily aligned in amanufacturing process.

The photodetector 400 is used to sense the amount of light emitted fromthe light source 111 traveling toward the display pixel 310 andreflected from the display pixel 310 without being emitted to a frontside of the display panel 300.

The light source controller 500 may select and drive some of theplurality of light emitting elements 112 based on the amount of lightdetected by the photodetector 400. For example, an alignment state ofthe light emitting elements 112 may be determined by comparing the casewhere only the light emitting elements 112 of the even-numbered columnsare driven by the light source 111 and the case where only the lightemitting elements 112 of the odd-numbered columns are driven. That is,the light source 111 may be controlled to drive only the light emittingelements 112 at locations corresponding to the non-pixel region 320 bydetermining whether the light emitting elements 112 at locationscorresponding to the non-pixel region 320 are the odd-numbered columnsor the even-numbered columns.

FIG. 8 is a cross-sectional view showing a schematic configuration of anillumination device 1006 according to another example embodiment.

The illumination device 1006 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and a light deliverer 206 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 300.

The light deliverer 206 includes a first meta-lens 236 disposed on thethird surface SUa of the substrate SU and a second meta-lens 237disposed on the fourth surface SUb. The first meta-lens 236 includes aplurality of first nanostructures NS7 and a shape distribution of theplurality of first nanostructures NS7 is set such that the firstnanostructures NS7 operates as one convex lens. The second meta-lens 237includes a plurality of second nanostructures NS8 and a shapedistribution of the plurality of second nanostructures NS8 is set suchthat the second nanostructures NS8 also operates as one convex lens.

The shape distributions of the plurality of first nanostructures NS7 andthe plurality of second nanostructures NS8 may be determined such thatthe first meta-lens 236 and the second meta-lens 237 have the same focaldistance f1 as shown in FIG. 8.

FIG. 9 is a cross-sectional view showing a schematic configuration of anillumination device 1007 according to another example embodiment.

The illumination device 1007 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and the light deliverer 206 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 300.

The illumination device 1007 of the example embodiment differs from theillumination device 1006 of FIG. 8 in that a microlens array 600 isfurther disposed between the light deliverer 206 and the display panel300 and the remaining configuration thereof is substantially the same.The microlens array 600 includes a plurality of microlenses 610respectively facing the plurality of non-pixel regions 320 of thedisplay panel 300. Light focused on the non-pixel region 320 by thefirst meta-lens 236 and the microlens 610 spreads toward a front side ofthe display panel 300 at a wider angle of view than when focused by thefirst meta-lens 236.

The presence or absence of the microlens array 600 and a refractingpower of the microlens 610 may be determined considering a detaileddistribution of flood illumination to be illuminated toward the frontside of the display panel 300. Flood illumination is illumination of agenerally uniform light distribution, and may be needed to adjustuniformity according to a distance from an object and a shape of theobject.

FIG. 10 is a cross-sectional view showing a schematic configuration ofan illumination device 1008 according to another example embodiment.

The illumination device 1008 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and a light deliverer 208 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 300.

The illumination device 1008 of the example embodiment differs from theillumination device 1006 of FIG. 8 in a detailed shape distribution ofthe first nanostructures NS9 and second nanostructures NS10 respectivelyprovided in a first meta-lens 238 and a second meta-lens 239constituting the light deliverer 208.

Shape distributions of the plurality of first nanostructures NS9 and theplurality of second nanostructures NS10 may be determined such that thefirst meta-lens 238 has a shorter focal distance than the secondmeta-lens 239. The plurality of second nanostructures NS10 may have theshape distribution implementing the focal length f1, and the pluralityof first nanostructures NS9 may have the shape distribution implementinga focal length f2 shorter than the focal length f1.

A degree by which the refractive power of the first meta-lens 238 isdifferent from the refractive power of the second meta-lens 239 may bedetermined considering a detailed distribution shape of floodillumination to be illuminated toward a front side of the display panel300 in the similar manner as in the illumination device 1007 of FIG. 9.

FIG. 11 is a cross-sectional view showing a schematic configuration ofan illumination device 1009 according to another example embodiment.

The illumination device 1009 includes the display panel 300 having atransmission window for transmitting light, the light source 110disposed below the display panel 300 to emit light toward the displaypanel 300, and a light deliverer 209 disposed between the light source110 and the display panel 300 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 300. Areflective structure 700 is disposed between the light deliverer 209 andthe display panel 300 to change a path of the light toward the pluralityof display pixels 310 to be directed to the non-pixel region 320.

The light deliverer 209 includes a meta shaper 240 disposed on thefourth surface SUb of the substrate SU. The meta-shaper 240 collimatesand shapes the light emitted from the light source 110, considering ashape of the reflective structure 700, such that light directed towardthe non-pixel region 320 of the display panel 300 via the reflectivestructure 700 and light directly directed toward the non-pixel region320 of the display panel 300 from the light source 110 are generallyemitted in a front side of the display panel 300 at a uniformdistribution. The meta-shaper 240 includes a plurality of nanostructuresof a sub-wavelength dimension. The plurality of nanostructures may havea shape distribution such that the amount of light directed toward thereflective structure 700 is generally similar to the amount of lightdirected directly to the non-pixel region 320 from the light source 110.

The reflective structure 700 includes a plurality of inclined surfaces700 a and 700 b that are inclined with respect to the third surface SUaof the substrate SU. The inclined surfaces 700 a and 700 b may be mirrorcoated surfaces that reflect light. The reflective structure 700 mayinclude a reflective metal material. A shape of the reflective structure700, for example, an inclination angle of the inclined surfaces 700 aand 700 b or a size of the reflective structure 700, may be determinedconsidering a distribution of flood illumination to be formed on thefront side of the display panel 300. This also relates to the shapedistribution of the nanostructures constituting the meta-shaper 240. Forexample, based on the shape, size, and the like of the reflectivestructure 700, the shape distribution of the nanostructures constitutingthe meta-shaper 240 may be determined such that a light distribution ofemitted light toward the reflective structure 700 meets a predeterminedrequirement.

FIG. 12 is a cross-sectional view showing a modified example of areflective structure 710 that may be employed in the illumination device1009 of FIG. 11.

The reflective structure 710 may be a high refractive index structurehaving total reflection surfaces 710 a and 710 b that cause totalreflection according to a difference in a refractive index as shown inFIG. 12, but embodiments are not limited thereto. The reflectivestructure 710 may have various shapes including a total reflectionsurface.

FIG. 13 is a cross-sectional view showing a schematic configuration ofan illumination device 1010 according to another example embodiment.

The illumination device 1010 includes a display panel 301 having atransmission window for transmitting light, the light source 110disposed below the display panel 301 to emit light toward the displaypanel 301, and a light deliverer 210 disposed between the light source110 and the display panel 301 to transmit the light emitted from thelight source 110 to the transmission window of the display panel 301.

The illumination device 1010 of the example embodiment is different fromthe illumination devices of the above-described example embodiments inthat the transmission window of the display panel 301 includes onenon-pixel region 322 in which the display pixel 310 is not located.

A location of the non-pixel region 322 may be formed at any location ona display surface of the display panel 301. Such a display panel 301 maybe formed in such a manner of removing pixels of a certain region in adisplay pixel arrangement of, for example, the typical display panel 30as shown in FIG. 2B. The non-pixel region 322 may have a diameter ofabout 5 mm to about 10 mm.

The light deliverer 210 includes a meta-shaper 242 disposed on thefourth surface SUb of the substrate SU. The meta-shaper 242 collimatesand shapes the light emitted from the light source 110, considering asize, a location, a shape, etc. of the non-pixel region 322, such thatthe light emitted from the light source 110 forms a beam cross-sectionsimilar to the size of the non-pixel region 322 at the location of thenon-pixel region 322, and then is diffused and emitted toward a frontside of the display panel 300. The meta-shaper 242 includes a pluralityof nanostructures of a sub-wavelength. The plurality of nanostructuresmay have a shape distribution such that the nanostructures collect, forexample, the light of the light source 110 on a first side 310 a that isthe display surface of the display panel 301 to the beam cross-sectionsize corresponding to the non-pixel region 322, and then diffuse andemit the light.

The illumination device 1010 of the example embodiment employs themeta-shaper 242 that sets the shape distribution of the nanostructure soas to be able to perform beam forming with a desired light distributionto use the non-pixel region 322 of a relatively small size compared tothe above-described illumination devices 1001 to 1009, thereby reducingthe sacrifice of the display pixel 310.

The illumination devices 1001 to 1010 of the above-described exampleembodiments may be employed in various electronic apparatuses that usethe concept of illuminating an object through a display panel.

FIG. 14 is a block diagram showing a schematic configuration of anelectronic apparatus 3000 according to an example embodiment.

The electronic apparatus 3000 includes an illumination device 3100providing flood illumination toward an object OBJ, a sensor 3300receiving light reflected from the object OBJ, and a processor 3200performing an operation for obtaining information about the object OBJfrom the light received from the sensor 3300.

The electronic apparatus 3000 may also include a memory 3400 in whichcode or data for execution of the processor 3200 is stored.

The illumination device 3100 includes a light source, a light deliverer,and a display panel, and illuminates the object OBJ through atransmission window of the display panel by changing a distribution ofthe light of the light source, and may employ one of the illuminationdevices 1001 to 1010 of the above-described example embodiments, acombination thereof, and a modified form may be employed.

Between the illumination device 3100 and the object OBJ, opticalelements for adjusting a direction such that light L_(FL) of theillumination device 3100 is directed to the object OBJ or an additionalmodulation may be further disposed.

The illumination device 3100 may illuminate the object OBJ with floodlight L_(FL). The flood light L_(FL) illuminates the entire object OBJat a time with a uniform light distribution. Here, the uniform lightdistribution does not may not be a uniformity of 100% but anillumination target region of the object OBJ may be generally uniformlyilluminated. Therefore, a detailed configuration of the light delivererof the illumination device 3100, that is, a shape distribution ofnanostructures provided in the light deliverer, may be determined suchthat a desired uniformity distribution of the flood light L_(FL) isimplemented according to a location and a shape of the object OBJ. Theobject OBJ may be the face of a user of the electronic apparatus 3000.The location of the object OBJ may be about 30 cm to about 1 m from theillumination device 3100, but embodiments are not limited thereto.

The sensor 3300 senses light L_(r) reflected by the object OBJ. Thesensor 3300 may include an array of light detection elements. The sensor3300 may further include a spectroscopic element for analyzing the lightL_(r) reflected from the object OBJ for each wavelength.

The processor 3200 performs the operation for obtaining the informationabout the object OBJ from the light received by the sensor 3300, and mayalso manage the entire processing and control of the electronicapparatus 3000. The processor 3200 may obtain the information about theobject OBJ, for example, obtain and process two-dimensional orthree-dimensional image information, and may also generally controldriving of a light source provided in the illumination device 3100 or anoperation of the sensor 3300, etc. The processor 3200 may also determinewhether the user is authenticated or the like based on the informationobtained from the object OBJ and may execute other applications.

The memory 3400 may store code for execution in the processor 3200,various execution modules executed by the electronic apparatus 3000, anddata for the various execution modules. For example, the memory 3400 maystore program code used in the arithmetic operation for the processor3200 to obtain the information of the object OBJ, and code such as anapplication module that may be executed using the information of theobject OBJ. Also, the memory 3400 may store a communication module, acamera module, a moving image reproduction module, an audio reproductionmodule, and the like as a device that may be additionally provided inthe electronic apparatus 3000 and a program for driving the device.

A result of the arithmetic operation in the processor 3200, that is,information about a shape and a location of the object OBJ, may betransmitted to another electronic apparatus or unit as needed. Forexample, the information about the object OBJ may be transmitted to acontroller of the other electronic apparatus using the information aboutthe object OBJ. The other unit to which the result is transmitted may bea display device or a printer that outputs the result. In addition, theother unit may include a smartphone, a cellular phone, a personaldigital assistant (PDA), a laptop, a PC, various wearable devices, andanother mobile or non-mobile computing device, but embodiments are notlimited thereto.

The memory 3400 may include at least one storage medium of a flashmemory type, a hard disk type, a multimedia card micro type, a card typememory (e.g., SD or XD memory), random access memory (RAM), staticrandom access memory (SRAM), read only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), programmable read-onlymemory (PROM), an optical disc, a magnetic disc, and an optical disc,and the like.

The electronic apparatus 3000 may be, for example, a portable mobilecommunication device, a smart phone, a smart watch, a personal digitalassistant (PDA), a laptop, a PC, another mobile or non-mobile computingdevice, but embodiments are not limited thereto. The electronicapparatus 3000 may be an autonomous driving device such as an unmannedvehicle, an autonomous drive vehicle, a robot, a drone, or the like, oran Internet of things (IoT) device.

FIG. 15 is a perspective view showing an example of an externalappearance of the electronic apparatus 3000 of FIG. 14.

The electronic apparatus 3000 may have a display of full screen type asshown in FIG. 15. That is, the electronic apparatus 3000 may bebezel-less type that almost an entire area of a front side of theelectronic apparatus 3000 is display surface. Further, a shape of thedisplay surface 3100 a may be a notch-free rectangular shape.

As described above, the illumination device according to the exampleembodiments may be disposed at a back side of a display panel andilluminate a front side of the display panel through transmissionwindows which are uniformly distributed on an entire display surface orformed in one region of a predetermined size on a display surface. Thus,a bezel-less and notch-free display of the illustrated externalappearance may be applied to the electronic apparatus 3000.

Specific implementations described in the example embodiment areexamples and do not in any way limit the scope of the disclosure. Also,connections or connecting members of lines between components shown inthe figures illustrate examples of functional connections and/orphysical or circuit connections, which may be a variety of functionalconnections, physical connections, or circuit connections that may bereplaced or additionally provided s in actual devices.

The above-described illumination device may emit light from a lightsource arranged on a back side of a display panel to a front side of thedisplay panel.

Therefore, the light source necessary for various sensors may be moreeffectively arranged without affecting the area of display surface ofthe display panel.

For example, the above-described illumination device may be employed ina bezel-less type mobile device or the like.

It should be understood that example embodiments described herein shouldbe considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each exampleembodiment should typically be considered as available for other similarfeatures or aspects in other embodiments.

While example embodiments have been described with reference to thefigures, it will be understood by those of ordinary skill in the artthat various changes in form and details may be made therein withoutdeparting from the spirit and scope as defined by the following claims.

What is claimed is:
 1. An illumination device comprising: a displaypanel comprising a first surface configured to display an image, asecond surface opposite to the first surface, a plurality of displaypixels disposed between the first surface and the second surface, and atransmission window configured to transmit light incident on the secondsurface through the first surface; a light source disposed at the secondsurface of the display panel and configured to emit light to an objecttoward the display panel; and a light deliverer disposed between thelight source and the display panel, the light deliverer configured todeliver the light emitted from the light source to the object as floodillumination through the transmission window, wherein the lightdeliverer comprises a plurality of nanostructures having a shapedimension smaller than that of a wavelength of the light emitted fromthe light source.
 2. The illumination device of claim 1, wherein thetransmission window comprises a plurality of non-pixel regions, whereinthe plurality of display pixels are configured to reflect the lightemitted from the light source, and wherein the plurality of displaypixels and the plurality of non-pixel regions are alternately provided.3. The illumination device of claim 2, wherein a fill factor of across-sectional area occupied by the plurality of display pixels on thefirst surface is 50% to 60%.
 4. The illumination device of claim 2,wherein the light deliverer comprises: a substrate comprising a thirdsurface facing the display panel and a fourth surface facing the lightsource; a meta-mirror disposed on the third surface and comprising aplurality of first nanostructures having a shape dimension smaller thanthat of the wavelength of the light emitted from the light source,wherein the plurality of first nanostructures have a shape distributionsuch that the plurality of first nanostructures is configured to operateas a mirror in which an aperture is formed in a center portion, and ameta-lens disposed on the fourth surface and comprising a plurality ofsecond nanostructures having a shape dimension smaller than that of thewavelength of the light emitted from the light source, wherein theplurality of second nanostructures have a shape distribution such thatthe light emitted from the light source is directed toward the aperture.5. The illumination device of claim 4, wherein the shape distribution ofthe plurality of first nanostructures is determined such that themeta-mirror is configured to operate as a concave mirror with respect tothe display panel.
 6. The illumination device of claim 4, wherein thelight source is provided asymmetrically with respect to the aperture. 7.The illumination device of claim 2, wherein the light deliverercomprises: a substrate comprising a third surface facing the displaypanel and a fourth surface facing the light source; a first meta-lensdisposed on the third surface and comprising a plurality of firstnanostructures having a shape dimension smaller than that of thewavelength of the light emitted from the light source, wherein theplurality of first nanostructures have a shape distribution such thatthe plurality of first nanostructures are configured to converge thelight to the plurality of non-pixel regions, and a second meta-lensdisposed on the fourth surface and comprising a plurality of secondnanostructures having a shape dimension smaller than that of thewavelength of the light emitted from the light source, wherein theplurality of second nanostructures have a shape distribution such thatthe plurality of second nanostructures collimate the light emitted fromthe light source to correspond to the first meta-lens.
 8. Theillumination device of claim 7, wherein the shape distribution of theplurality of first nanostructures is determined such that the firstmeta-lens is configured to operate as a plurality of first convex lensesprovided to face the plurality of non-pixel regions, and wherein theshape distribution of the plurality of second nanostructures isdetermined such that the second meta-lens is configured to operate as aplurality of second convex lenses provided to face the plurality offirst convex lenses, respectively.
 9. The illumination device of claim7, wherein the shape distribution of the plurality of firstnanostructures is determined such that the first meta-lens is configuredto operate as a plurality of first convex lenses provided to face theplurality of display pixels and the plurality of non-pixel regions, andwherein the shape distribution of the plurality of second nanostructuresis determined such that the second meta-lens is configured to operate asa plurality of second convex lenses provided to face the plurality offirst convex lenses, respectively.
 10. The illumination device of claim9, wherein the light source comprises a plurality of light emittingelements arranged to correspond to the plurality of display pixels andthe plurality of non-pixel regions, respectively.
 11. The illuminationdevice of claim 10, further comprising: a photodetector configured tosense an amount of the light emitted from the light source reflectedfrom the plurality of display pixels; and a light source controllerconfigured to select and drive a number of the plurality of lightemitting elements based on the amount of light detected by thephotodetector.
 12. The illumination device of claim 7, wherein the shapedistribution of the plurality of first nanostructures and the shapedistribution of the plurality of second nanostructures are determinedsuch that the first meta-lens and the second meta-lens each isconfigured to operate as a convex lens, respectively.
 13. Theillumination device of claim 12, further comprising a microlens arraydisposed between the first meta-lens and the display panel, themicrolens array comprising a plurality of microlenses facing theplurality of non-pixel regions, respectively.
 14. The illuminationdevice of claim 12, wherein the shape distribution of the plurality offirst nanostructures and the shape distribution of the plurality ofsecond nanostructures are determined such that a focal length of thefirst meta-lens is shorter than a focal length of the second meta-lens.15. The illumination device of claim 2, further comprising a reflectivestructure provided between the light deliverer and the display panel,the reflective structure configured to reflect the light emitted fromthe light source and directed toward regions of the plurality of displaypixels to be directed toward a non-pixel region.
 16. Illumination deviceof claim 15, wherein the light deliverer comprises: a substratecomprising a third surface facing the display panel and a fourth surfacefacing the light source, and wherein the plurality of nanostructureshaving a shape distribution shaping the light emitted from the lightsource such that an amount of light directed toward the reflectivestructure from the light source is similar to an amount of lightdirected directly toward the transmission window from the light source.17. The illumination device of claim 1, wherein the transmission windowcomprises one region in which the plurality of display pixels are notprovided.
 18. The illumination device of claim 17, wherein a diameter ofthe transmission window is 5 mm to 10 mm.
 19. The illumination device ofclaim 17, wherein the plurality of nanostructures have a shapedistribution such that the light emitted from the light source isfocused on the first surface to a beam cross-sectional sizecorresponding to the transmission window, and then diffused and emittedto a front side of the display panel.
 20. An electronic apparatuscomprising: an illumination device comprising: a display panelcomprising a first surface configured to display an image, a secondsurface opposite to the first surface, a plurality of display pixelsdisposed between the first surface and the second surface, and atransmission window configured to transmit light incident on the secondsurface through the first surface; a light source disposed at the secondsurface of the display panel and configured to emit light to an objecttoward the display panel; and a light deliverer disposed between thelight source and the display panel, the light deliverer configured todeliver the light emitted from the light source to the object as floodillumination through the transmission window, wherein the lightdeliverer comprises a plurality of nanostructures having a shapedimension smaller than that of a wavelength of the light emitted fromthe light source; a sensor configured to receive light reflected fromthe object; and a processor configured to obtain information about theobject based on the light received by the sensor.